Applicant has invented a novel rock reamer drill bit some times referred to as a rock drill bit which is capable of producing improved drilling operation an increased drilling efficiency which bit is less likely to bind, twist or break due to the accumulation of residue or other friction producing means between the bit body and the bore being drilled. It is the purpose of the present bit construction to provide means to stabilize the operation of drill bits during drilling operations, which bit increases the penetration rate, removes residue from therearound and reduces friction between the bit and the bore surface. This is accomplished with the present bit construction by providing means for facilitating the movement of drilling residue past the bit by pulverizing any such drilling residue including any fragments therein that are produced during drilling as the residue is carried away from the drilling face by the drilling fluid and as the residue moves between the outer surface of the bit body and the bore being drilled. This is done to minimize friction between the body of the bit and the surface being drilled. The present bit construction therefore facilitate removal of the drilling residue, minimizes the possibility for hang ups and binding or twisting due to material accumulating around the bit body and prevents accumulation of the drilling residue behind the bit thereby making it easier to drill and to remove the bit from a bore and it leaves a clean hole for placing a blasting agent. These are very important considerations for drill bits including bits used to drill into rock that forms a mine passage where the drilling is done to accommodate the placing of explosive charges to blast and loosen the surrounding rock. The construction of the present bit also substantially extends its useful life thereby representing a substantial savings to mine operators. The full body design of the present bit also holds the carbons in proper striking position, thereby extending the life of the bit.
In the past it has been the practice to construct drill bits for drilling into rock that have head portions of substantially larger diameter than the trailing tubular body portions. Such constructions use the annular space between the body portions of the bits and the bore surfaces as passages for the residue carried by the drilling fluid and produced during drilling. The tubular body portions of such drill bits receive the threaded end portions of a tubular drive rods used for rotating the drill bit during the drilling operation. However, the known bits have had no provision apart from the fluid used to facilitate removal by flushing to further pulverize the residue as it moves past the bit, and as a result known bits tend to accumulate residue between the bit body and the bore during drilling and this has produced friction therebetween and accompanying binding and twisting of the bits in the bores. Such binding and twisting distorts and in some cases cracks or breaks the bits. For the same reasons the known bits tend to excessively load the drive rods due to the friction and binding and generally require more power than is desired to drive them thereby further increasing the chances of producing the problems indicated. As a result of these conditions the diameter of known bit bodies have often been made substantially smaller than the diameter of the head portion to provide as much space between the bit bodies and the bores as possible for the residue to pass. As this space is increased either the diameter of the head portion increases beyond what is the most desireable condition or the bit body becomes too small and weak. While making the diameter difference large may minimize the chance for a bit binding in a bore it also means that the ratio of the diameter of the bit body to the diameter of the bit head may not be the most desirable or efficient.
Furthermore, no known rock bit has means for agitating and further pulverizing the residue as it moves along the side of the bit body to further reduce the size of the particles in the residue and to facilitate unobstructed movement of the residue from the bore face to the rear of the bit and from there out through the bore. Not only does no known bit include means for pulverzing the residue as it moves past the bit body, the present bit has means at the rear end of the bit for agitating and pulverizing residue that may accumulate behind the bit in the bore. This is especially a problem if the bore slopes downwardly away from the entrance which can make it especially difficult to remove the bit. The present bit has endwardly extending projections on the rear end of the bit body which acts to stir up and agitate the residue that accumulates behind the bit. The present construction therefore has several novel features, as explained, and it has been found in practice that the present bit construction substantially improves the drilling operation, makes the drilling operation more efficient, and with less chance for the bit twisting, binding or breaking, it reduces the driving force necessary to rotate the bit, and the present bit construction is much likely to bind in a bore due to the accummulation of drilling residue around the outer surface of the bit body and behind the bit. The present bit construction therefore operates better and more efficiently than known rock drill bits, is less likely to be damaged and is easier to drill with and to withdraw from bore. The full body construction also increases penetration rate, and leaves a clean hole for inserting the blasting agent.